1. Field of the Invention
This invention relates to an improved combination of a power transmission belt that is adapted to be operated in an endless path and a tensioner for such belt as well as to the tensioner per se and to methods of making and operating such combination and the tensioner therefor.
2. Prior Art Statement
It is known in the art to provide a combination of a power transmission belt that is adapted to be operated in an endless path and a tensioner for the belt, the tensioner comprising a support means fixed relative to the belt, a belt engaging means carried by the support means and being movable relative thereto, and biasing means operatively associated with the support means and the belt engaging means urging the belt engaging means relative to the support means in a belt tensioning direction and against the belt with a force to tension the belt.
Examples of combinations of the above mentioned type are provided in the following five U.S. patents:
(1) U.S. Pat. No. 3,413,866--Ford PA0 (2) U.S. Pat. No. 4,108,013--Sragal PA0 (3) U.S. Pat. No. 4,145,934--Sragal PA0 (4) U.S. Pat. No. 4,151,756--Binder et al PA0 (5) U.S. Pat. No. 4,249,425--Watson PA0 (6) U.S. Pat. No. 3,623,377--Lewis et al PA0 (7) U.S. Pat. No. 4,024,772--Kumm PA0 (8) U.S. Pat. No. 3,995,505--Leunberger PA0 (9) Japanese Patent application publication No. 20294/1972 PA0 (10) FIG. 65 on page 182 of Automotive Handbook.
It appears from item (1) above that a tension spring urges an idler pulley in tensioning engagement against a belt.
It appears from item (2) above that a compression spring urges an idler pulley in tensioning engagement against a belt.
It appears from item (3) above that a leaf spring urges an idler pulley in tensioning engagement against a belt.
It appears from item (4) above that a plurality of bimetal dish-shaped springs or spring washers are disposed in various stacked relations thereof and urge an idler pulley in tensioning engagement against a belt.
It appears from item (5) above that pneumatic means is adapted to threadedly adjust an idler pulley rod of a belt tensioner wherein a pair of dish-shaped springs or spring washers urge the idler pulley in tensioning engagement against a belt.
It is also known to provide variable speed pulleys.
For example, see the following two U.S. patents:
It appears that the variable speed pulley of item (6) above increases its effective diameter as the speed of rotation thereof increases, the pulley construction being adapted for operating on the opposed sides of a V-belt construction.
It appears that the variable speed pulley of item (7) above is adjustable under the force of a piston and cylinder arrangement and is adapted to operate on the bottom driving surface of a belt construction or on the opposed sides of a V-belt construction.
It is also known to provide a combination of a power transmission belt that is adapted to be operated with a varying speed of movement in an endless path and a tensioner comprising a support means fixed relative to the belt, a belt engaging means carried by the support means and being movable relative thereto, biasing means operatively associated with the support means and the belt engaging means urging the belt engaging means relative to the support means in a belt tensioning direction and against the belt with a force to tension the belt, and control means operatively associated with the biasing means to progressively decrease its urging force on the belt engaging means as the speed of movement of the belt progressively increases from a certain low speed of movement thereof to a certain high speed of movement thereof, the tensioner comprising a pulley having a variable speed of rotation and being adapted to progressively reduce its effective diameter as the speed of rotation thereof progressively increases from a certain low speed of rotation thereof to a certain high speed of rotation thereof, the pulley having a rotatable hub that comprises the support means and an effective diameter defining means carried by the hub that comprises the belt engaging means, the biasing means being operatively disposed between the hub and the diameter defining means.
For example, see the following United States Patent, Japanese Patent Application and publication:
It appears that each variable speed pulley of items (8), (9) and (10) above has the diameter defining means thereof comprising angled sheaves that engage the opposed angled driving surfaces of the belt.